See
here for a full guide. Basically, from where you are:
1) Get the trophy in Vogel's office. Fill it with beer in the kitchen.
2) Give it to Biff (the big guy). Punch him when he's drunk.
3) Go past him, to the south corridor. Talk to/beat the guard, get the key to Henry's cell in the room behind him.
4) Now go to the north corridor, find the door with the alarm wires sticking out, unlock it with the key.
But you'll definitely regret not having the pass later on...
